Atmospheric pressure changes and outdoor temperature changes in relation to spontaneous pneumothorax.

STUDY AIMS To examine the influence of atmospheric pressure (AP) and temperature changes on the incidence of idiopathic spontaneous pneumothorax (SP). METHODS From December 1991 through November 1993, 115 consecutive SP cases were selected. Patients were included after being in Amsterdam at least 1 full day before contracting the SP. Differences in air temperature and AP (provided hourly by the national weather bureau) for the days of the SP occurrence and the days previous to it were recorded to measure influences of air temperature and AP. The correlation between days with lightning and SP and clustering of SP was evaluated. RESULTS SP occurred on 14.7% of the days in the 2-year period. There was no relationship between SP and a rise or fall in AP (Poisson regression). There was an average temperature rise of 0.57 degrees C from the day prior to the day of the SP, compared with a 0.08 degrees C fall on the days without SP. This difference is statistically significant and was consistent over the four seasons and both years. Seventy-three percent of the SP cases were clustered. A relationship between SP and thunderstorms was found. CONCLUSIONS AP differences do not seem to influence the chance of developing SP. SP occurs in clusters, and more often 1 to 2 days after thunderstorms. Whether the identified temperature rise prior to the SP is a causative factor is unlikely; coexisting weather phenomena might explain this unexpected finding and should be studied in the future.